Question: $-\dfrac{5}{6} + \dfrac{3}{5} = {?}$
$ = - {\dfrac{5 \times 5}{6 \times 5}} + {\dfrac{3 \times 6}{5 \times 6}} $ $ = - {\dfrac{25}{30}} + {\dfrac{18}{30}} $ $ = - \dfrac{{25} + {18}}{30} $ $ = -\dfrac{7}{30}$